The typical prior art approaches for electrically interconnecting a flexible circuit carrier ("flex circuit" or "flex") to a printed circuit board ("PCB") are costly due to the number of parts and labor involved in the prior art interconnection approaches. There are three commonly used approaches for electrically interconnecting a PCB to a flex circuit.
In the first approach, the flex circuit has a thermoplastic header overmolded or soldered to a connector end of the flex circuit. The PCB has a mating connector header and the two ends are then pressed or snapped together to make the electrical interconnection between the PCB and flex circuit. In order to keep the mated parts from loosening due to shock or vibration, this interconnection technique will sometimes require the use of screws or other types of fasteners on both sides of the connection to assure mechanical stability of the interconnection.
A second prior art interconnection approach relies on exposed pads on the flex to make contact to a header located on the PCB. In order to keep the flex from loosening from the header, the header may have a plastic piece that press fits or snaps in after the flex is inserted such as a zero-insertion-force connector.
The third interconnection approach typically used in the art involves soldering the flex directly to the PCB. While reliable and cost effective, this scheme produces an assembly which can not be serviced if the assembly becomes inoperable for any reason. Thus, once the interconnection is performed a new assembly or a new flex circuit must be used, thereby increasing the overall repair cost.
Major drawbacks to the first two schemes noted above are cost and reliability. The direct material cost of the header plus the labor time required to assemble the connectors to the PCB and flex circuit. The third scheme has the major problem that once the flex is soldered to the PCB, the assembly needs to be replaced, since attempting to disconnect the soldered flex from the PCB requires a lot of labor in order not to damage the assembly.
A need thus exists for a scheme for electrically interconnecting a flex circuit to a PCB that provides for both good electrical connections between the PCB and flex and also simplifies the manufacturing of the assembly.